/*
 * $Id: PDFPages.java,v 1.16 2003/03/07 08:25:47 jeremias Exp $
 * ============================================================================
 *                    The Apache Software License, Version 1.1
 * ============================================================================
 * 
 * Copyright (C) 1999-2003 The Apache Software Foundation. All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modifica-
 * tion, are permitted provided that the following conditions are met:
 * 
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 
 * 3. The end-user documentation included with the redistribution, if any, must
 *    include the following acknowledgment: "This product includes software
 *    developed by the Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself, if
 *    and wherever such third-party acknowledgments normally appear.
 * 
 * 4. The names "FOP" and "Apache Software Foundation" must not be used to
 *    endorse or promote products derived from this software without prior
 *    written permission. For written permission, please contact
 *    apache@apache.org.
 * 
 * 5. Products derived from this software may not be called "Apache", nor may
 *    "Apache" appear in their name, without prior written permission of the
 *    Apache Software Foundation.
 * 
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * APACHE SOFTWARE FOUNDATION OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLU-
 * DING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * ============================================================================
 * 
 * This software consists of voluntary contributions made by many individuals
 * on behalf of the Apache Software Foundation and was originally created by
 * James Tauber <jtauber@jtauber.com>. For more information on the Apache
 * Software Foundation, please see <http://www.apache.org/>.
 */ 
package org.apache.fop.pdf;

// Java
import java.util.List;
import java.util.ArrayList;

/**
 * class representing a /Pages object.
 *
 * A /Pages object is an ordered collection of pages (/Page objects)
 * (Actually, /Pages can contain further /Pages as well but this
 * implementation doesn't allow this)
 */
public class PDFPages extends PDFObject {

    /**
     * the /Page objects
     */
    protected List kids = new ArrayList();

    /**
     * the number of /Page objects
     */
    protected int count = 0;

    // private PDFPages parent;

    /**
     * create a /Pages object. NOTE: The PDFPages
     * object must be created before the PDF document is
     * generated, but it is not written to the stream immediately.
     * It must also be allocated an object ID (so that the kids
     * can refer to the parent) so that the XRef table needs to
     * be updated before this object is written.
     *
     * @param objnum the object's number
     */
    public PDFPages(int objnum) {
        super();
        setObjectNumber(objnum);
    }

    /**
     * add a /Page object.
     *
     * @param page the PDFPage to add.
     */
    public void addPage(PDFPage page) {
        page.setParent(this);
        this.incrementCount();
    }
    
    /**
     * Use this method to notify the PDFPages object that a child page
     * @param page the child page
     */
    public void notifyKidRegistered(PDFPage page) {
        this.kids.add(page.referencePDF());
    }

    /**
     * get the count of /Page objects
     *
     * @return the number of pages
     */
    public int getCount() {
        return this.count;
    }

    /**
     * increment the count of /Page objects
     */
    public void incrementCount() {
        this.count++;
        // log.debug("Incrementing count to " + this.getCount());
    }

    /**
     * @see org.apache.fop.pdf.PDFObject#toPDFString()
     */
    public String toPDFString() {
        StringBuffer sb = new StringBuffer(64);
        sb.append(getObjectID()).
            append("<< /Type /Pages\n/Count ").
            append(this.getCount()).
            append("\n/Kids [");
        for (int i = 0; i < kids.size(); i++) {
            sb.append(kids.get(i)).append(" ");
        }
        sb.append("] >>\nendobj\n");
        return sb.toString();
    }

}